Backyard Aquaponics
A place to discuss aquaponics

I have had my system for a while, but recently harvested most of my fish. I have some new ones now, I have bass, bluegill, koi and catfish. I got these fish from an aquafarm, the same one I always go to and have always had good luck with them.

Well, now I have an issue and everyone is dying. I think I have some sort of parasite in the water, or something causing this, but not sure how to proceed.

I have attached a couple of pictures of the latest death, but I also had another catfish, blue gill and two more kois dead this morning.

Nitrites and Ammonia are zero and I Have not really been feeding much since this all started. Nitrates are high, but not higher than I have had before. Interestingly enough, the bass have shown no signs of problem, they are fat and happy.

Anyone got any ideas? Anything else I can provide that can help me out here?

One of the pics of the tail fin looks "raked" as if a toothy critter had it in its mouth.

I know this feeling, maybe the bass are the culprits.

Thanks Manny, it is possible one of the other catfish was trying to eat it, but I have never really seen that happen, and this was one of the bigger fish in the tank. The bass are in a completely different tank, that tank is piped into the same system, I just house them in a different tank.

Here are some pictures of what I am seeing on one of my fish that is still alive.

I thought fin rot, then googled red marks on catfish skin and found this:
https://www.petcha.com/red-blotch-disea ... s-catfish/


I just pulled #6 dead fish. this one 2-3 inches long. All 6 fish have been small ones under 5 inches.

So note to self, no more mixing smalls and bigs together.

Would be nice to hear more experience/advice/fix chime in your your case.

I'm thinking that this may be a disease issue that's followed an attack by some predator. Looking at the photos, especially the first ones you posted, I see what could be claw marks on the upper part of the tail. Near the gill on one of the other pics is what could be an infected wound from a claw. Some of the red marks might also be infected puncture wounds or just an infection that's unrelated to an attack but might be stress related.